[llvm] [SPIRV] Add a `SPIRVTypeInst` type with some guardrails (PR #179947)

[Juan Manuel Martinez Caamaño via llvm-commits]

jmmartinez wrote:

> > Some buildbots build with `-Werror` :(
> > It seems elsewhere in LLVM we just leave a doxygen string like this:
> > ```c++
> > /// @deprecated Use reportFatalInternalError() or reportFatalUsageError()
> > /// instead.
> > [[noreturn]] LLVM_ABI void report_fatal_error(const char *reason,
> >                                               bool gen_crash_diag = true);
> > ```
> 
> Kind of expected, unfortunately. Plan B: we file an issue keep track of the remaining uses of `SPIRVType`. Does that work?

Filed https://github.com/llvm/llvm-project/issues/180788

https://github.com/llvm/llvm-project/pull/179947